Aims of the present invention are:                polarizing, transparent optical products, which are notably useful in the spectacles trade, and which have an original structure and interesting properties; as well as        a method of manufacturing said products. This method is adaptable according to variants and is particularly interesting in that it can be qualified as a universal method (with reference to the surface of the product in question), in that it is easy to implement, and in that it can be implemented away from the site of manufacture of the products in question.        
Products of this type have already been proposed according to prior art which are associated with methods of manufacture, which are more or less complex to implement.
The polarizing products of the prior art contain, in their structure, according to a first variant, a polarizing film which is based on a polymer (of poly(vinyl alcohol), polyethylene terephthalate, for example) which is drawn uniaxially and which is impregnated with at least one colorant (iodinated compounds or dichroic colorants); and according to a second variant, a film of colorant(s) having polarizing properties based on colorant(s) per se.
Two techniques have been developed within the context of the first variant. According to the first, which is described notably in WO-A-01 875 79, U.S. Pat. Nos. 5,286,419, 5,412,505 and US-A-2001/0028435, the film of impregnated polymer is incorporated within the structure of the product, embedded in said structure. Said film, which is formed beforehand, is introduced during the manufacture of the product, on the site of manufacture of said product. This technique of manufacture of polarizing products is relatively arduous to implement. According to the second of these techniques, which is described notably in U.S. Pat. No. 5,286,420 and JP-A-09 258 009, the film of impregnated polymer is formed beforehand and then fixed, notably by adhesion, to the surface of the product. Said film is incorporated on the surface. More particularly in this context, the problem of the stability of the polymer film arises (which polymer has a tendency to relax and therefore to lose its polarizing properties) and those of the effective protection against moisture and heat, of said polymer film.
Within the context of the second variant, a film of colorant(s) having polarizing properties is generated, which is permanently orientated on a surface of the product. The following procedure is generally carried out: a lyotropic solution of at least one colorant is deposited and dried on a surface which is treated beforehand in order to have microgrooves, which are arranged in parallel. This technique and its theory are described notably in US patent U.S. Pat. No. 2,400,877. In this document, said technique is not mainly described and in any case, it is illustrated only with reference to a glass surface and to a glass substrate. The problem of the stability of the film on the surface is not raised. In this document, the production of films of colorant(s), which are flexible and peelable is also envisaged, by incorporating an intermediate film of paraffin oil, mineral oil, barium stearate or of a resin, on the glass. In the French patent applications FR-A-2,568,568 and FR-A-2,590,889, the technique of formation of microgrooves, which are parallel, on the surface of the substrate and then the deposit and the drying of a solution of colorants, in order to generate a film of colorants having polarizing properties, is taken up and improved with regard to the protection of said film generated. This film is generated directly on the surface of the substrate, which is of inorganic or organic glass. All the examples in fact concern inorganic glasses. It is easily understood that the implementation of any technique which implies the formation of the film of colorant(s) on the surface of the substrate implies an adaptability of said technique to the state of the surface of each of the substrates in question. Thus, the formation of parallel microgrooves by rubbing or brushing on the surface of organic glasses necessitates a regulation as a function of the hardness of the surface of each organic glass. Within the context of this second variant, the techniques implemented hitherto remain relatively complicated and make use of bulky equipment. Thus, they are not implemented in the prescription laboratory for the preparation of solar lenses and/or polarizing ophthalmic lenses.
In such a context, it is to the merit of the inventors to have conceived a novel type of polarizing, transparent optical product, which has good performance and which is particularly interesting in that it can be obtained by an original method of manufacture, a method:                which is easy to implement,        able to integrate touching up,        able to be implemented for the manufacture of solar lenses and/or ophthalmic lenses in the prescription laboratory for said lenses,        that can be considered universal, with reference to the surface of the product in question. Said method is in fact suitable whatever the shape is, whatever the constituent material is, and whatever the state of the surface of said surface is.        